The invention relates to a drill for drilling of stacked work pieces. The drill comprises a drill body having chip flutes and a first cutting insert releasably secured to a first cutting insert site of the drill body and a second cutting insert releasably secured to a second cutting insert site of the drill body. The cutting inserts are provided on opposite sides of a first center line of the drill in the axially forward end of the drill. The drill has a cylindrical basic shape which is defined by a diameter and is rotatable about the first center line. The first cutting insert is provided at least partly radially inside the second cutting insert.
A known drill has two identical hexagonal indexable cutting inserts arranged in recesses in the front surface of the drill shank. The active cutting edges of the cutting inserts are broken such that the bisector of each cutting edge becomes parallel with the center line of the drill.
At drilling there is usually formed a breakout slug when drilling through a work piece. During drilling of stacked work pieces when plates are stacked on top of each other, said slug cannot disappear from the machining area since an adjacent plate prevents the movement of the slug. The slug will rotate with the known drill until the feed force becomes large enough to break the slug. At this large feed force there is a risk for cutting edge and/or drill breakdown.
The object of the present invention is to solve the above-mentioned problem .